Sulfonate-functionalized HDNE probe enables detection of neutrophil elastase in colitis mice

Neutrophil elastase (NE) has emerged as a key protease in inflammatory bowel disease pathogenesis, serving as both a diagnostic marker and therapeutic target. This study establishes a comprehensive methodology for monitoring NE activity in inflammatory conditions using a sulfonate-modified hemicyanine-based probe (HDNE). Through systematic evaluation, HDNE demonstrated remarkable aqueous solubility and biocompatibility, with negligible cytotoxicity observed in macrophage cultures. The probe exhibited high sensitivity toward NE with a linear response range up to 2.5 U/L and maintained excellent selectivity against competing biological species. In a dextran sulfate sodium-induced colitis model, HDNE enabled non-invasive visualization of NE activity, revealing distinct spatiotemporal patterns correlating with disease progression. Quantitative analysis confirmed significant signal enhancement in inflammatory regions, achieving maximum contrast at 90 min post-injection. Ex vivo validation further verified the accuracy of in vivo measurements, while histopathological assessment confirmed minimal systemic toxicity. These findings collectively validate HDNE as a reliable tool for investigating NE dynamics in inflammatory environments, providing valuable insights for disease monitoring and therapeutic assessment.